The invention relates to vibration sensing.
Gas turbine engines are commonly equipped with one, or more, accelerometers to detect vibration. Because the accelerometers sometimes malfunction, back-up accelerometers are often provided. The accelerometers add weight to the engine. They also increase costs of manufacturing, design, and maintenance. Further, some accelerometers are fragile, and easily damaged.
The invention mitigates some, or all, of the disadvantages just identified. One form of the invention detects vibration by analyzing an existing pulse train which is produced by an existing sensor, and presently used for speed measurement. Under the invention, the existing pulse train is used to indicate both speed and vibration.